This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To determine the factors underlying quality paternal care in male marmosets. With poor parenting or parental absence, there are a number of psychosocial disorders that confound human health. Marmosets are one of the few mammalian species whose social organization/family structure bears resemblance to that of humans. These studies are designed to determine the hormonal pathway for priming paternal care behaviors in biparental males who show extensive parental care. With the first year of the grant ending, we have all specific aims ongoing. In specific aim 1 we have found that increased estradiol significantly stimulates males to be more attentive to infant distress signals in na[unreadable]ve males. Males who have not been fathers before show little responsiveness to infant stimuli while experienced fathers show significant response to infant stimuli. In specific aim 2&3 we are measuring dopamine, oxytocin, vasopressin and prolactin in pituitary cells of intact anterior and posterior pituitaries as well as each pituitary cultured separately for experienced and na[unreadable]ve males. Initial results are revealing significant differences between experienced fathers and na[unreadable]ve males in their levels of prolactin and oxytocin but not vasopressin. Experienced fathers have significantly higher prolactin and oxytocin than na[unreadable]ve fathers. This research project, now in its second year, relies on WNPRC Assay Services and Animal Services.